<template>
    <div class="header">
      <input type="text" v-model="newMsg">
      <button @click="add">确定</button>
    </div>
</template>

<script setup>
import { ref } from 'vue'

const newMsg = ref('')

const emits = defineEmits(['addMsg'])  // 定义事件
const add = () => {
    emits('addMsg', newMsg.value)   // 发布
}

</script>

<style lang="scss" scoped>

</style>